Problem: Evaluate the following expression when $d = 3$ and $c = 10$. $4$ $d$ $ + 6$ $c$ $ + 9$
Explanation: Substitute $3$ for ${d}$ and $10$ for ${c}$ $ = 4{(3)} + 6{(10)} + 9 $ $ = 12 + 60 + 9 $ $ = 81$